InterPro domain: IPR012171

This entry includes fatty acid desaturase family members from bacteria, fungi, plants and animals. Proteins in this family contain the fatty acid desaturase domain ( IPR005804 ). The eukaryotic members, including human FADS1 and FADS2, are fusion proteins containing an N-terminal cytochrome b5-like domain and a C-terminal multiple membrane-spanning desaturase portion [ 1 ].

Three human fatty acid desaturase genes have been identified, fatty acid desaturase 1-3 (FADS1-3) [ 2 ]. FADS1 and FADS2 encode delta-5 desaturase (D5D) and delta-6 desaturase (D6D) respectively. They are membrane-bound enzymes that catalyse the rate-limiting formation of endogenous long-chain polyunsaturated fatty acid (PUFA). FADS3 is a ceramide desaturase that produces sphinga-4,14-dienine-containing ceramides (SPD ceramides). FADS3 also acts as a methyl-end fatty acyl coenzyme A (CoA) desaturase that introduces a cis double bond between the preexisting double bond and the terminal methyl group of the fatty acyl chain. [ 3 ].

1. cDNA cloning, genomic structure, and chromosomal localization of three members of the human fatty acid desaturase family. Genomics 66, 175-83
2. Fatty acid desaturase 1 gene polymorphisms control human hepatic lipid composition. Hepatology 61, 119-28
3. Biosynthesis of the anti-lipid-microdomain sphingoid base 4,14-sphingadiene by the ceramide desaturase FADS3. FASEB J 34, 3318-3335